In vitro Activity of Ceftaroline Against an International Collection of Kingella kingae Isolates Recovered From Carriers and Invasive Infections

Background:Improvements in blood culture techniques and molecular-based diagnostics have led to increased recognition of Kingella kingae as an invasive human pathogen causing bacteremia, septic arthritis, osteomyelitis and endocarditis in young children. Serious disease and potentially life-threatening complications of infection due to K. kingae necessitate timely identification and appropriate antimicrobial therapy. Ceftaroline is a fifth-generation broad spectrum cephalosporin that possesses activity against Gram-negative and Gram-positive pathogens similar to third-generation cephalosporins, but also includes methicillin-resistant Staphylococcus aureus. This study reports the in vitro activity of ceftaroline and comparator agents against an international collection of K. kingae isolates. Methods:A collection of 308 K. kingae isolates was obtained primarily from children with bacteremia, endocarditis, osteoarticular infections or from asymptomatic pediatric carriers. Isolates were tested for antibiotic susceptibility using Clinical and Laboratory Standard Institute broth microdilution methodology and screened for beta-lactamase production using a nitrocefin chromogenic test. Results:Ceftaroline inhibited all K. kingae isolates at <= 0.06 mg/L (MIC50/90, 0.015/0.03 mg/L). Ceftaroline MICs were similar to results with ceftriaxone (MIC50/90, 0.015/0.015 mg/L), meropenem (MIC50/90, 0.015/0.015 mg/L) and ampicillin-sulbactam (MIC50/90, 0.06/0.06 mg/L). Ceftaroline MICs were slightly lower than MICs for cefuroxime and amoxicillin/clavulanate (MIC50/90, 0.06/0.12 mg/L). MICs were high for clindamycin (MIC50/90, 2/4 mg/L) and oxacillin (MIC50/90, 4/8 mg/L). Sixteen isolates (5.2%) yielded a positive nitrocefin test indicating production of beta-lactamase; ceftaroline demonstrated equivalent MICs against beta-lactamase-positive and beta-lactamase-negative strains (MIC50/90, 0.015/0.3 mg/L). Conclusions:The potent activity of ceftaroline against this large international collection of K. kingae isolates supports further clinical evaluation in children.